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Discussion Starter · #1 ·
Truck felt like it was missing when I started it. Low on power when driven. Rough idle. P1316 code thrown. AE injector buzz test showed #5 was very quiet compared to others, P1275 code thrown. I ordered a new valve cover gasket and injector harness kit from Diesel o rings.com. I know to check all connections and wiring harnesses. I recently went through my whole engine harness recently already. I plan on ohm checking the pins soon on that side cover. My question is would the injector make any noise on a buzz test if the connectors are bad? It makes some buzz but very faint. Is my injector most likely bad? I can switch #3 and #5 to see if the problem follows the injector. I would like to know if i should just order new injectors before going through the trouble. I want to go to stage 1.5 injectors anyway, but now is not really a good time. Any input is appreciated. Thanks, Jason
 

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P1275 is a high to low side open on the injector. It could be a bad injector solenoid or bad wiring between the IDM and the solenoid. Problems with wiring far outnumber problems with injectors. You could switch the injectors if you wanted to. If P1275 is thrown again, that would point to a problem with the wiring. If the high to low open moves to cylinder #3, the injector is the problem. I would personally go after wiring problems first - much easier than the trouble of swapping injectors and much more likely to be the cause of the problem.
 

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...or the IDM is failing.
 

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Discussion Starter · #4 ·
Will a failing IDM affect one injector only? Or is one bank more likely to be affected? Also can anyone answer if a bad injector will buzz during a test even if it's a soft sound?
 

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The IDM has a switching transistor for each injector that supplies the ground signal, so yes, one of those could fail.
Or the power supply to one bank can fail, or ......
You may have corrosion in the IDM connector on that one circuit that suck some of the voltage to the injector solenoid.
The list goes on.....
 

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Discussion Starter · #6 ·
Problem fixed! UVCH connector was 50% unplugged. I'm surprised only #5 was affected. Reconnected and tested everything was perfect. Still going to replace the gasket and harness when the parts come in. Will be checking and replace the drivers side as well. Goes to show how simple things can cause big problems. It pays to have a quality scan equipment and help from the greatest diesel forum around. Thanks friends for your help.
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Glad you got it fixed. To keep it from happening again, lookup the "25 cent" mod. It's really 50 cents since you need a quarter for each side. The 25 cent mod involves grinding a little bit off each side of a quarter so that it will fit in the gap between the UVCH harness plug and mating connector. The quarter fills that space and keeps the plastic latches engaged so that the connector won't back out. Very easy to do.
 

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Discussion Starter · #8 ·
I considered the 25cent mod. I feel better about replacement. Hopefully the new ones have improved the connection.
 

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Discussion Starter · #9 ·
On a side note. Anyone know the torque specs on the valve cover gasket?
 

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Valve covers are 96 in-lbs (8 ft-lbs). When I replaced my valve cover gaskets, I still used the 25 cent mod even though they were new. Cheap insurance to ensure the harnesses stay locked together. I think there is a plastic shim that is made specifically for this purpose, but I'm sure it costs more than 25 cents.
 

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I considered the 25cent mod. I feel better about replacement. Hopefully the new ones have improved the connection.
The currently manufactured UVCHs have improved latches, with little nubs to help keep them engaged. The plastic clips don't work with the new style UVCH, but do with the original ones without the nubs. Don't know if the 25cent mod works on the newer UVCHs.
 

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Had this happen in 2008 on driver's side at home in AZ where I could deal with it easily, thanks to thedieselstop. Ford wanted $22 for small plastic part to insert in the connector. I told them for that $$, I would cut up my credit card first and use that to fix it. As it was, found a teflon washer in the shed that worked just fine. Didn't do the other side because of the ole "if it ain't broke don't fix it" view.

Seven years later as we passed through Eagle River on our way from Denali to Homer on a 12,000 mi Alaska road trip, I gave klhansen a distant hat tip for his assistance. Then of all things, the unfixed side started after we left Tok headed toward Chicken on our way to Dawson City, YK. Same symptoms and Scan Gauge threw same codes as first time, but the other bank. Was hoping to reach Dawson, but was ready to fix it anywhere in between in the wilderness if I had to. Dawson Visitor Center let me work on it there. A Canadian quarter fixed it. That was 13 and 5 years ago respectively. Still have the truck. Runs great! And thanks again to thedieselstop and those who dedicate themselves to maintaining our trucks!
 
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